The present technique relates to a transfer device for transferring data. For example, the present technique relates to a transfer device for connecting a processing apparatus for processing data with plural system boards equipped with a memory for storing data.
Some information processing apparatuses incorporate plural units that are physically separated from one another. One unit is, for example, a system board on which a central processing unit (CPU), a memory module, etc. are mounted or an input/output (I/O) board on which I/O devices for a hard disk device, a peripheral component interconnect (PCI) device, etc. are mounted. The system board and the I/O board are connected to a crossbar switch as a transfer device for transmitting/receiving data.
The crossbar switch includes a data buffer control unit. A queue buffer in the data buffer control unit stores data transmitted or received between system boards or I/O boards. The queue buffer stores data transmitted from any system board in the order in which the data was received. The queue buffer is composed of a flip-flop or a memory device such as a random access memory (RAM). Data stored in the memory device is at risk of being corrupted. A soft-error is one of the factors that corrupt data. The soft-error is a phenomenon that an amount of charges accumulated in a memory device is changed when an α beam having charges and emitted from uranium contained in a semiconductor package or a wiring material impinges on the memory device. If a critical charge amount of a flip-flop is reduced due to a low-voltage operation or the like, the soft-error easily occurs and system reliability is lowered.
To describe an example of mechanisms for increasing system reliability, two queue buffers having the same capacity are prepared to construct a completely duplexed queue buffer. However, such a duplexed queue buffer causes an increase in hardware components and in turn, an increase in system cost.
Technique of the related art is disclosed in Japanese Laid-open Patent Publication No. 53-093735 and Japanese Laid-open Patent Publication No. 57-195397.